Process for forming cement



Dec. 5, 1933. R M, LA D 1,937,898

PROCESS FOR FORMING CEMENT Filed March 14, 1932 Patented Dec. 5, 1933 UNITED STATES PATENT. OFFICE ApplicationiMarch 14, 1932. Serial No. 598,723

, LClaim. (01. 25-155) The object of my invention is to provide a process for forming cement blocks to be used for conduit purposes, the blocks having a multiple number of ducts therein, the process being l 35 simple and comparatively easy to practice.

In connection with the manufacture of cement blocks having a plurality of openings or ducts therein it has been found extremely difficult to arrange a web between the ducts against collapsing while the block isbeing formed.

Cement pipe has heretofore been manufactured employing the packer head principle wherein the cement is poured into a form and a packer head revolved at a high rate of speed passing upwardly through the cement and providing the opening in the pipe, the packer head serving to compact the cement and to define a complete opening in the cement. In such a case where only one opening is provided the problem is not so difficult because the mold extending. all around the pipe serves as a resisting force against the action of the packer head as it revolves and forces and compacts the cement therearound.

When employing two or more packer heads within a cement block, the problem of retaining the cement between the adjacent ducts is of extreme importance. It is my purpose to provide a process for forming a cement block containing a plurality of ducts therein in such a manner that the cement-like material between the ducts will be held against breaking down or collapsing during the process of manufacturing the block and while the material is in its plastic condition.

My process includes the employment of a plu-- rality of packer heads which revolve in opposite directions and are synchronized so that projections carried by the packer heads and forming a part thereof register with each other so that one projection serves as a wall to receive the force imposed upon the web between the adjacent ducts by the projection of an adjacent packer head, while the packer heads are revolving.

My process may be employed for forming cement blocks having a plurality of ducts therein, which ducts may be arranged in rows in any direction.

Figure l is a perspective view of one of the cement blocks used for conduit purposes, having a plurality of ducts therein.

Figure 2 is a top plan view of a mold having the cement material therein with a plurality of packer heads illustrated in section.

Figure 3 is a similar view illustrating two packer heads in a position different from Figure 2.

Figure 4 is a diagrammatic view illustrating 'a device for practicing mypr'ocess wherein the packer heads are arranged in rows; and

Figure 5 illustrates a packer head.

On the accompanying drawing, I have used the 9 reference character A to indicate generally a cement block having a plurality of ducts or openings 10 therein. A mold or casing 12, of any suitable kind, is employed and placed upon its end with its top end open. 2

A plurality of shafts 14 are arranged which have a pair of wings l6 suitably connected to the shaft by bolts or the like 18. A portion of the shaft 14 and the wings 16 form what I call a packer head assembly. Just below the wingszf. 16 is a circular member 20 which serves as a trowel for finishing the interior of the duct as the entire packer head assembly moves upwardly through the cement material.

The use of a single packer head member H11 connection with the manufacture of sewer pipe is a well known art at this time. Between the ducts or openings 10 in the block A are portions 22 in the form of a narrow web. It is the portions 22 that do not have any rigid mold against 2.2 them and it is therefore necessary to provide means to prevent the collapsing of the portions 22 as the packer heads revolve.

In my process, I arrange a plurality of packer heads, each mounted upon a shaft revolving 133. in opposite directions. In Figure 2 I have illustrated arrows 24 to show the direction of rotation of the packer heads which may be the first and third from the left hand side of the drawing. The arrows 26 indicate rotation of theijzfi packer heads second and fourth from the left hand side of the drawing. It will be noted that any two adjacent packer heads revolve in opposite directions. In addition to revolving the packer heads in opposite directions it is news-12.9

sary that each packer head be synchronized so that the wings 16 travel adjacent the web 22 at the same time, or in registry with each other.

The wings of two adjacent packer heads travel symmetrically relative to each other. ment material which forms the web 22 is held against collapsing by the arrangement of the wings revolving symmetrically and serving as opposing walls to prevent collapsing of the maas it is formed. In packer heads as used in myui The ce-L1:.

process for making a cement block having a plurality of ducts therein there occurs exactly the same thing. The cement is compacted and after the packer heads have moved entirely through the cement a plurality of openings in each block are formed.

In Figure 4 I have illustrated the arrangement of the packer heads when blocks are formed with rows of ducts. The shafts containing the packer heads thereon are synchronized so that the wings always register and move symmetrically. This arrangement just described tends to retain the material forming the web between the ducts against collapsing, which would happen if it were not for the force of one packer head wing being resisted by the packer head wing of the next adjacent packer head.-

In Figure 4, in additon to the webs 22 thereare webs 28, that must be taken into consideration, and in this case all of the packer heads are synchronized so that the wings of one packer head registers with all of the adjacent packer head wings during rotation of the packer heads.

In Figure 4 I have also shown dotted lines 30 which illustrate the position of the packer heads and their wings so that all of the material between four adjacent ducts is likewise held against collapsing. Arrows in Figure 4 indicate the direction of travel of the packer heads.

I claim:

The process of forming a conduit block of cement-like material having more than one duct by simultaneously passing a plurality of packer heads, having wings thereon, longitudinally through the material while synchronously revolving said packer heads with the wing of one packer head opposite the wing of the adjacent packer head to form a resisting force between packer heads to prevent collapsing of the material between the ducts while plastic and while said wings are adjacent the thinnest part of said material between the ducts.

RUSSELL M. LA DUE. 

